JP5688693B2 - Organic transparent conductor, organic transparent conductor forming ink and method for producing the same - Google Patents

Description

  The present invention relates to an organic transparent conductor, an ink for forming an organic conductor, and a method for producing them.

  Transparent conductors are used for display panels of image display devices such as liquid crystal displays, electroluminescent displays, and electrochromic displays, and panels of solar cells, and are used as electrodes for voltage application and charge injection. Moreover, it has been widely used for a touch panel which is a two-dimensional information input device. Furthermore, the application to the conductive or antistatic plastic packaging material having transparency in which the generation of static electricity is suppressed and the packaging material is easy to confirm the transparent inclusion is also being studied.

  Conventionally, as a transparent conductor material, a panel in which a thin film of indium tin oxide (ITO), indium zinc oxide (IZO), or fluorine-doped tin oxide (FTO), which are metal oxides, is deposited on a glass substrate or plastic sheet has been used. Has been. In particular, there is a concern that indium used for the metal oxide will be depleted of resources in the near future and supply and demand will be tight. These metal oxides have a high cost for forming a material, and there is a problem that a considerable cost of, for example, an organic electroluminescent element or an organic solar cell is spent on the metal oxide film. Furthermore, the metal oxide has a poor electronic or chemical interaction with an organic substance, causing a problem in, for example, the efficiency of charge injection into the charge transport layer of the organic EL element.

From such a viewpoint, attempts to form a conductor film using a material in which conductive fine particles are dispersed in a transparent polymer are described in, for example, Patent Documents 1 to 3 below. In recent years, there has been an attempt to coat a substrate with a polythiophene-based solvent-soluble conductive polymer thin film (see Patent Document 4).
However, in the method using conductive fine particles, the interaction between the conductive fine particles is strong, and it is difficult to uniformly disperse in the transparent polymer. Further, in the step of applying the resulting polymer solution onto the substrate, there is a problem that the conductive polymers are associated with each other by the shearing force of the application. Moreover, in the method using a conductive polymer, it is difficult to realize complete colorless and transparent, and it is slightly colored. For this reason, there is a problem that coloring becomes conspicuous when the film is thick.

  In order to eliminate such inconveniences, the present inventors have found that after forming a carbazole film by electrolytic polymerization, a transparent conductor film is produced by bringing a metal into contact (Patent Document 5). . According to this method, although a transparent conductor with high transparency can be obtained, it is necessary to peel off the film formed on the substrate as an electrode in order to produce by electropolymerization. Further, since it is formed as a film on a substrate, there is a problem in practical use, such as a large scale-up required to obtain a film with a large area. Therefore, further improvement is necessary for practical use.

Japanese Patent Laid-Open No. 7-219697 JP 2000-123658 A Japanese Patent Laid-Open No. 3-167590 JP 2002-60736 A JP 2007-165199 A

  An object of the present invention is to provide a transparent conductor and a transparent conductor-forming ink that have good transparency and conductivity and are easy to produce.

  As a result of diligent studies on the above problems, the present inventors have found that the above problems can be solved by bringing a metal into contact with poly (N-alkylcarbazole), and the present invention has been completed.

(1) A method for producing a transparent conductor, comprising a step of bringing poly (N-alkylcarbazole) obtained by polymerizing at least one N-alkylcarbazole represented by the following general formula into contact with a metal.
(In the formula, n is an integer of 1 or more, and at least one hydrogen of alkyl may be replaced with at least one group selected from hydroxy, carboxyl, sulfo and amino.)
(2) The method for producing a transparent conductor according to (1), wherein the contacting step is performed in a liquid phase.
(3) The method for producing a transparent conductor according to (1) or (2), wherein the metal used in the contacting step is a molten metal.
(4) The method for producing a transparent conductor according to any one of (1) to (3), wherein the polymerization is chemical polymerization.
(5) A transparent conductor produced by the method according to any one of (1) to (4).
(6) A poly (N-alkylcarbazole) obtained by polymerizing at least one N-alkylcarbazole represented by the following general formula is dissolved in a solvent to form a poly (N-alkylcarbazole) solution, and the solution and the metal A method for producing an ink for forming a transparent conductor, which comprises a step of contacting the transparent conductor.
(In the formula, n is an integer of 1 or more, and at least one hydrogen of alkyl may be replaced with at least one group selected from hydroxy, carboxyl, sulfo and amino.)
(7) A transparent conductor forming ink comprising a step of bringing a metal into contact with a poly (N-alkylcarbazole) solution obtained by chemical polymerization of at least one N-alkylcarbazole represented by the following general formula: Production method.
(In the formula, n is an integer of 1 or more, and at least one hydrogen of alkyl may be replaced with at least one group selected from hydroxy, carboxyl, sulfo and amino.)
(8) The method for producing an ink for forming a transparent conductor according to (6), wherein the polymerization is chemical polymerization. (9) A transparent conductor forming ink produced by the method according to any one of (6) to (8).

  According to the present invention, it is possible to provide a transparent conductor and a transparent conductor-forming ink that have good transparency and conductivity and are easy to produce.

It is a NMR chart of Nn-octylcarbazole. 2 is an NMR chart of poly (Nn-octylcarbazole). It is a transmission spectrum of the poly (Nn-octyl carbazole) film | membrane before vapor-depositing tin and after vapor-depositing tin. It is a transmission spectrum of the poly (Nn-heptylcarbazole) film | membrane before vapor-depositing tin and after vapor-depositing tin. It is the poly (Nn-heptyl carbazole) film | membrane before (A) which vapor-deposits tin, and (B) after vapor-depositing tin (photograph substitute drawing). It is a transmission spectrum of the poly (Nn-nonylcarbazole) film | membrane before vapor-depositing tin and after vapor-depositing tin. It is the transmission spectrum of the spin coat film of poly (Nn-octyl carbazole) and the spin coat film only of poly (Nn-octyl carbazole) brought into contact with the tin vapor deposition film in a 1,2-dichloroethane solution. It is a transmission spectrum of a spin coat film of poly (Nn-octylcarbazole) and a spin coat film of poly (Nn-octylcarbazole) only in contact with a commercially available aluminum vapor deposited mylar film in 1,2-dichloroethane solution. . It is a transmission spectrum of the spin coat film | membrane of the poly (Nn-octyl carbazole) contacted with granular magnesium and zinc in chloroform. It is the transmission spectrum of the spin coat film | membrane of the poly (Nn-octyl carbazole) contacted with granular indium and gallium in chloroform. It is the transmission spectrum of the film | membrane which pressure-bonded the spin coat film | membrane of poly (Nn-octyl carbazole), the molten gallium, and the gallium indium alloy. It is the transmission spectrum of the spin coat film | membrane of the poly (N-ethyl carbazole) contacted with the granular aluminum in chloroform. It is the transmission spectrum of the spin coat film | membrane of the poly (Nn-docosyl carbazole) contacted with the granular tin in chloroform. It is a vacuum ultraviolet photoelectron spectroscopy spectrum of a spin coat film of poly (Nn-octylcarbazole) and poly (Nn-docosylcarbazole).

Hereinafter, embodiments of the present invention will be described.
In the present invention, an N-alkylcarbazole polymer having a polymerization degree of 2 or more obtained by polymerizing N-alkylcarbazole is referred to as poly (N-alkylcarbazole).

The method for producing a transparent conductor according to the present embodiment includes a step of bringing a metal into contact with poly (N-alkylcarbazole) obtained by polymerizing at least one N-alkylcarbazole represented by the following general formula. It is characterized by including.

In the above formula, n is an integer of 1 or more, and alkyl (C _n H _{2n + 1} ) is replaced with at least one group in which one or more hydrogens are selected from hydroxy, carboxyl, sulfo and amino. It may be. The carbon bonded to the N-position of carbazole is preferably a primary carbon or a secondary carbon.
Even if the poly (N-alkylcarbazole) used in the present invention is a homopolymer obtained by polymerizing one type of N-alkylcarbazole, a copolymer obtained by copolymerizing two or more types of N-alkylcarbazole It may be. Further, as poly (N-alkylcarbazole), even if it is only one kind of poly (N-alkylcarbazole), two or more kinds of poly (N-alkylcarbazole) composed of alkyl having different carbon numbers are mixed. It may be used.
Since poly (N-alkylcarbazole) is colored and has low transparency, it can be made into a transparent conductor forming ink or a transparent conductor by the method of the present invention.
Examples of poly (N-alkylcarbazole) include tetramer and dimer as shown in the following formula.
In the following formula, n is the same as the above formula. The degree of polymerization of poly (N-alkylcarbazole) is preferably 2 to 1,000, more preferably 4 to 100, and particularly preferably 4 to 22 from the viewpoints of transparency and strength.

(Process to contact with metal)
In the production method of the present invention, the conductive film can be made transparent by bringing poly (N-alkylcarbazole) into contact with a metal. The metal to be contacted is not particularly limited, but it is preferable to cause a metal having a work function smaller than the ionization potential of poly (N-alkylcarbazole) to react with the metal. Specific examples of such metals include aluminum, indium, zinc, titanium, manganese, iron, copper, silver, tin, antimony, sodium, magnesium, gallium, potassium or calcium, and alloys thereof. Of these, aluminum, tin, zinc, indium, and gallium are particularly preferably used.

In the present invention, poly (N-alkylcarbazole) may be brought into contact with metal by vapor deposition, sputtering, plating, electrodeposition, electron beam, mechanochemical, contact with molten metal, and poly (N Examples thereof include a liquid-phase contact method in which a metal vapor-deposited film or metal powder is added to a solution in which -alkylcarbazole) is dissolved. In the present invention, the molten metal refers to a metal obtained by melting the metal at a temperature equal to or higher than the melting point.
Alternatively, the metal may simply be brought into physical contact. Poly (N-alkylcarbazole) to be brought into contact with the metal is a film prepared by electrolytic polymerization described later, a powder prepared by chemical polymerization described later (solid state), or a solution state in which these films and powders are dissolved in an organic solvent. But you can. The poly (N-alkylcarbazole) used in the present invention has high solubility in an organic solvent, and can be present as a poly (N-alkylcarbazole) solution. Therefore, by adopting a method of contacting with a metal in the liquid phase, a transparent conductor forming ink described later can be produced, which is preferable.

Since polycarbazole is not dissolved in a solvent, in the conventional method for producing a transparent conductor, a polycarbazole film is produced by electrolytic polymerization. In this method, a polycarbazole film has to be once formed on a conductive substrate, and then a transparent conductor is formed by depositing metal on the formed film. Therefore, it is not possible to produce a very large film, and it is necessary to remove the polycarbazole film formed on the conductive substrate from the conductive substrate. For practical use, it is easy to produce a transparent conductor. There was a need to improve.
However, since poly (N-alkylcarbazole) is highly soluble in organic solvents, a method of using a solution of poly (N-alkylcarbazole) dissolved in an organic solvent and contacting with a metal in the liquid phase should be used. Thus, a transparent conductor can be obtained. In this case, after bringing the poly (N-alkylcarbazole) solution into contact with the metal, the obtained solution can be used as a transparent conductor forming ink. Since this ink can form a transparent conductor by applying this ink, it is easy to produce. In addition, even when poly (N-alkylcarbazole) is produced as a film on a conductive substrate by conventional electrolytic polymerization, an organic solvent such as chloroform can be used without physically peeling the film from the conductive substrate. Since the poly (N-alkylcarbazole) film dissolves, it can be recovered by dissolving it.

  When poly (N-alkylcarbazole) and a molten metal are brought into contact with each other, a transparent conductive material is obtained by bringing a poly (N-alkylcarbazole) powder or a solution of poly (N-alkylcarbazole) into contact with the molten metal. The transparent conductor can also be formed by forming a poly (N-alkylcarbazole) film and then bringing the film into contact with a molten metal.

Specifically, after forming a poly (N-alkylcarbazole) film, the molten metal is applied to the obtained film and kept above the melting point of the molten metal, so that the transparent conductor film of the present invention can be easily prepared. Can be produced.
As the metal, in order to prevent thermal degradation of the poly (N-alkylcarbazole) film, it is preferable to use a metal or alloy having a melting point of 200 ° C. or less, and it is more preferable to use a metal or alloy having a melting point of 30 ° C. or less. Specifically, gallium (melting point 29.8 ° C.); alloy of gallium (75.5 wt%) and indium (24.5 wt%) (melting point 15.7 ° C.); gallium (62 wt%) and indium (25 wt%) and tin (13 wt%) alloy (melting point 5 ° C); gallium (67 wt%), indium (29 wt%) and zinc (4 wt%) alloy (melting point 13 ° C); Alloy of gallium (92 wt%) and tin (8 wt%) (melting point 20 ° C); Alloy of gallium (95 wt%) and zinc (5 wt%) (melting point 25 ° C); Gallium (95.5 wt%) %) And silver (4.5% by weight) (melting point: 25 ° C.). After applying the molten metal, the temperature is maintained at a temperature equal to or higher than the melting point of the metal, and pressure (specifically, 1.0 g which is the weight of the glass substrate itself in which a thin film is formed on a 1.5 × 1.5 cm ² film). It is a method of putting molten metal in a container and placing the glass with the thin film facing down on the container.

  In the step of contacting with the metal of the present invention, the obtained poly (N-alkylcarbazole) can be made colorless by bringing the metal into contact with the colored poly (N-alkylcarbazole). This is based on the difference in ionization potential between the poly (N-alkylcarbazole) -metal and the work function as a driving force, and the electrons are transferred from the contacting metal to the poly (N-alkylcarbazole). The cation radical or dication resulting from the color development of the alkyl carbazole) is bonded to disappear, and the colored poly (N-alkyl carbazole) is made colorless. Some of the electrons reduce adsorbed water present in the poly (N-alkylcarbazole). In order to transfer electrons from a metal to poly (N-alkylcarbazole), the work function of the metal is preferably smaller than the ionization potential of poly (N-alkylcarbazole). In addition, although the metal which loses electrons and is oxidized becomes an ion, the metal ion is bonded to a negative ion (anionic dopant) paired with a cation radical or dication in poly (N-alkylcarbazole) to form a colorless salt. Or is added to the water reduction reaction to form colorless metal oxides and hydroxides. That is, a galvanic corrosion reaction is caused between a metal and poly (N-alkylcarbazole), and a metal salt, a metal oxide, and a hydroxide can be formed.

The transparent conductor produced by the production method of the present invention has a transmittance of 70% or more at a wavelength of 450 to 700 nm in the transmission spectrum measurement, and has very high transparency. As shown in FIGS. 3, 4 and 6, poly (N-alkylcarbazole) increases the transmittance of its transmission spectrum by contact with a metal. Thereby, it can be judged that poly (N-alkylcarbazole) is in contact with the metal. In addition, the transparent conductor in the present invention is a conductor having a good electric conductivity and having an electric conductivity of 10 ⁻⁴ S · cm ⁻¹ or more, and is very excellent in electric conductivity. In addition, the transparent conductor in the present invention includes a film and a plate, and in the case of a film, the thickness is about 50 nm to 0.1 mm, and in the case of a plate, 0.1 mm. It may exceed.

  The poly (N-alkylcarbazole) used in the production method of the present invention is preferably a polymer obtained by polymerizing N-alkylcarbazole in which alkyl is bonded to the N-position of carbazole with primary carbon or secondary carbon. This polymer can be formed by electrolytic polymerization of N-alkylcarbazole, and can also be formed by chemical polymerization. The alkyl of poly (N-alkylcarbazole) is not particularly limited, but may be any alkyl having 1 or more carbon atoms (in the above formula, n represents 1 or more). From the viewpoint of easy commercial availability, alkyl having 22 or less carbon atoms (in the above formula, n is 22 or less) is preferable. Further, from the viewpoint of solubility in an organic solvent, alkyl having 2 or more carbon atoms (in the above formula, n represents 2 or more) is preferable. More preferably, it is an alkyl having 7 to 22 carbon atoms (in the above formula, n represents 7 to 22). In addition, one or more hydrogens of alkyl may be replaced with at least one group selected from hydroxy, carboxyl, sulfo and amino.

(Synthesis of N-alkylcarbazole)
N-alkyl carbazole, in which alkyl is bonded to the N-position of carbazole, is synthesized by dehydrohalogenation reaction between carbazole and an alkyl halide as an alkylating agent in the presence of a strongly basic alkali metal compound such as sodium hydride. can do. Alternatively, it can be synthesized by a dehalogenation reaction of carbazole potassium salt and alkyl halide. Note that when poly (N-alkylcarbazole) is synthesized by chemical polymerization using an oxidizing agent, the alkyl bonded to the N-position of carbazole is preferably a primary carbon or a secondary carbon. When the alkyl bonded to the N-position of carbazole is a tertiary carbon, the alkyl tends to be eliminated during polymerization, and it may be difficult to obtain the desired poly (N-alkylcarbazole).

(Alkyl halide)
The alkyl halide as the alkylating agent can be obtained from a reagent manufacturer. For handling in the laboratory, alkyl monobromides are easy to handle due to the rich variety of reactivity and alkyl. Available alkyl monobromides are specifically 1-bromopropane, 2-bromopropane, 1-bromobutane, 2-bromobutane, 1-bromo-2-methylpropane, 2-bromo-2-methylpropane, 1-bromo. -3-methyl-butane, 1-bromohexane, 2-bromohexane, 3-bromohexane, 1-bromomethylpentane, 1-bromoheptane, 3-bromoheptane, 4-bromoheptane, 1-bromo-5-methyl Hexane, 1-bromo-2-ethylhexane, 1-bromooctane, 2-bromooctane, 1-bromononane, 2-bromononane, 1-bromodecane, 1-bromoundecane, 1-bromododecane, 2-bromododecane, 1- Bromotridecane, 1-bromotetradecane, 2-bromotetradecane, 1-bromopentadecane Kan, 1-bromoheptadecane, 1-bromo-2-methylhexadecane, 1-bromooctadecane, 1-bromoeicosan, 1-bromodocosane, Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan Co., Ltd., Lancaster Etc.

(Synthesis of alkyl halides)
The alkyl halide can be obtained by a halogen hydrogen addition reaction of an alkene in addition to the alkyl monohalide. This reaction proceeds easily by adding hydrogen halide to the alkene solution. To obtain alkyl halides by alkene hydrohalide addition, see JOHN WILEY & SON, INC. It is convenient to synthesize alkyl monoiodide by hydrogen iodide addition reaction of alkene according to the method described in the published Organic Synthesis IV pages 543-544 (published in 1962).

  The available alkenes include 3,3-dimethyl-1-butene, 2-hexene, 3-hexene, 4-methyl-1-pentene, 4-methyl-2-pentene, 3,3-dimethyl-1-pentene. 4,4-dimethyl-1-pentene, 2-heptene, 3-heptene, 3-methyl-1-hexene, 4-methyl-1-hexene, 4-methyl-2-hexene, 5-methyl-1-hexene 5-methyl-2-hexene, 3,3-dimethyl-1-hexene, 3,4-dimethyl-1-hexene, 5-methyl-2-heptene, 5-methyl-3-heptene, 2-octene, trans -3-octene, trans-4-octene, 2-nonene, 4-nonene, 3,3,5-trimethyl-1-hexene, cis-2-decene, cis-4-decene, cis-5-decene, 5 Dodecene, 7-tetradecene, there is a cis-9- tricosene, available from Tokyo Chemical Industry Co., Ltd. and the like.

  By the above-described hydrogen iodide addition reaction of alkene, 2-iodo-3,3-butane, 3-iodohexane, 4-bromohexane, 2-iodo-4-methylpentane, 3-iodo-4-methylpentane, 2 -Iodo-3,3-dimethylpentane, 2-iodo-4,4-dimethylpentane, 3-iodo-heptane, 4-iodoheptane, 2-iodo-3-methylhexane, 2-iodo-4-methylhexane, 3-iodo-4-methylhexane, 2-iodo-5-methylhexane, 3-iodo-5-methylhexane, 2-iodo-dimethylhexane, 2-iodo-3,4-dimethylhexane, 2-iodo-4 , 4-hexane, 3-iodo-5-methylheptane, 4-iodo-5-methylheptane, 3-iodo-octane, 4-iodooctane, 5-iodo Kutan, 3-iodononane, 5-iodononane, 2-iodo-3,3,5-hexane, 3-iododecane, 4-iododecane, 6-iododecane, 6-iodo-dodecene, 8-tetradecene, 10-iodotricosane Can be obtained.

(Formation of poly (N-alkylcarbazole) by electrolytic polymerization)
A process of forming poly (N-alkylcarbazole) by electrolytic polymerization will be described. In the present invention, the electropolymerization means that a polymerizable monomer is polymerized by using a current-carrying means. Specifically, the monomer and the electrolyte are dissolved in a solvent, and a voltage is applied to the electrode for polymerization. Is the method. As a feature, since a catalyst is not used, a highly pure conductive polymer can be obtained.
First, the N-alkylcarbazole synthesized by the above method and the supporting electrolyte are dissolved in an electropolymerization solvent to prepare a solution containing N-alkylcarbazole.

  The concentration of N-alkylcarbazole in the solution is preferably 0.001 part by weight or more and 50 parts by weight or less, and 0.01 part by weight or more and 17 parts by weight or less when the electrolytic polymerization solvent is 100 parts by weight. The following is more preferable. When the amount is 0.001 part by weight or more, there is an effect that a structurally continuous polymer film can be obtained. When the amount is 0.01 part by weight or more, this effect becomes more remarkable. Moreover, there exists an effect that a solution viscosity can be reduced by making it 50 parts by weight or less, and a polymerization reaction can be performed with sufficient reaction rate, and this effect becomes more remarkable by making it 17 parts by weight or less.

  The solvent for electrolytic polymerization in the solution is not particularly limited as long as it can dissolve the N-alkylcarbazole and the supporting electrolyte and can achieve electrolytic polymerization, but has a relatively high dielectric constant. It is preferable that the solvent has Examples of the solvent for electrolytic polymerization include halogenated hydrocarbons such as dichloromethane, formamides such as dimethylformamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, alcohols such as methanol, lactones such as γ-butyrolactone, N-methyl-2, and the like. -Pyrrolidone such as pyrrolidone, carbonates such as propylene carbonate, and nitriles such as acetonitrile can be used. These can be used alone or in combination as appropriate. As the mixed solvent, for example, when a perchloric acid aqueous solution and methanol are mixed and used, a good polycarbazole film can be formed. Moreover, a solvent and water can be mixed and used. Specifically, for example, water (25% by volume) and methanol (75% by volume) are suitable as the mixed solvent.

The supporting electrolyte in the solution is not particularly limited as long as it can cause an electrochemical reaction, but it is preferable that the supporting electrolyte does not undergo an electrode reaction during electrolytic polymerization. Examples of the supporting electrolyte include HClO ₄ , (C ₄ H ₉ ) ₄ N ⁺ ClO ₄ ⁻ , (C ₃ H ₇ ) ₄ N ⁺ ClO ₄ ⁻ , (C ₂ H ₅ ) ₄ N ⁺ ClO ₄ ⁻ , ( CH ₃ ) ₄ N ⁺ ClO ₄ ⁻ , Li ⁺ ClO ₄ ⁻ , Na ⁺ ClO ₄ ⁻ , K ⁺ ClO ₄ ⁻ , H ⁺ ClO ₄ ⁻ , (C ₄ H ₉ ) ₄ N ⁺ BF ₄ ⁻ , (C ₄ H ₉ ) ₄ N ⁺ PF ₆ ⁻ , (C ₂ H ₅ ) ₄ N ⁺ BF ₄ ⁻ , (C ₂ H ₅ ) ₄ N ⁺ PF ₆ ⁻ , Li ⁺ BF ₄ ⁻ , Li ⁺ PF ₆ ⁻ are used. be able to. These may be used singly or may be used in appropriate mixture. When the solvent contains water, in addition to the above, NaCl, NaBr, Na ₂ SO ₄ , NaNO ₃ , LiCl, LiBr, LiNO ₃ , Li ₂ SO ₄ , KCl, KBr, KNO _3, K ₂ SO _4, etc. Can be included as a preferred supporting electrolyte option.

  The concentration of the supporting electrolyte is not limited as long as an electrochemical reaction can be caused. However, when the solvent is 100 parts by weight, the concentration may be 0.001 part by weight or more and 50 parts by weight or less. Preferably, the amount is 0.01 parts by weight or more and 50 parts by weight or less. When the amount is 0.001 part by weight or more, there is an effect that it is possible to sufficiently form an electric double layer, which is the driving force for electrolytic polymerization of N-alkylcarbazole. The effect is that the polymerization reaction can be carried out at a sufficient reaction rate. Specifically, 12.6 parts by weight is suitable for a mixed solvent of water (25% by volume) and methanol (75% by volume).

  The method for producing a transparent conductor by electrolytic polymerization includes a step of forming a poly (N-alkylcarbazole) by electrolyzing a solution containing a solvent for electrolytic polymerization, N-alkylcarbazole and a supporting electrolyte. Electrolysis is performed by immersing the anode and cathode in the above solution and applying a voltage between the anode and the reference electrode. Moreover, it can also carry out by applying a voltage between an anode and a cathode, without using a reference electrode.

  The anode is preferably a conductive material that is a metal that does not dissolve in electrolysis, and is preferably a metal such as Pt, Au, stainless steel, or a carbon material having conductivity. In addition, conductive oxides such as indium tin oxide (ITO) and tin oxide, conductive plastics, and semiconductors such as silicon and gallium arsenide can be used depending on conditions.

  The cathode is not particularly limited as long as it is a conductive material. For example, metals such as Pt, Au, Cu, Ni, and stainless steel, conductive oxides such as indium tin oxide (ITO) and tin oxide, conductive plastics, silicon, A semiconductor such as gallium arsenide can be used.

  The voltage applied between the anode and the reference electrode is preferably +0.5 V or more and +1.8 V or less, more preferably +0.5 V or more and +1.5 V or less with respect to the saturated calomel reference electrode. When the potential becomes a more noble potential, the alkyl of N-alkylcarbazole is eliminated, and 9,9'-dicarbazyl having low durability with respect to electric conductivity and energization may be generated. In addition, decomposition of the solvent for electropolymerization and the supporting electrolyte occurs, which tends to be undesirable for the electropolymerization of poly (N-alkylcarbazole). When the reference electrode is not used, the voltage applied between the anode and the cathode is preferably +0.9 V or more and +4 V or less, more preferably +1 V or more and +3 V or less for the same reason. Further, in the electrolysis without using the reference electrode, poly (N-alkylcarbazole) can be electropolymerized also by flowing a constant current between the anode and the cathode as long as the applied voltage falls within the above range. .

  In addition, the electrolysis of the solution in the present embodiment can be performed in the air, but is preferably performed in a nitrogen atmosphere in order to minimize the influence of oxygen in the air, and nitrogen bubbling is performed on the solution. Is more preferable.

  In addition, the electrolysis of the solution in the present embodiment is not limited, but may be −40 ° C. or higher and 40 ° C. or lower from the viewpoint of forming a poly (N-alkylcarbazole) film having relatively high electrical conductivity. preferable.

Poly (N-alkylcarbazole) formed by electrolysis is formed into a film on the anode. The film thickness depends on the amount of energization during electrolytic polymerization and the substituent of N-alkylcarbazole used as a raw material. Although it can be appropriately adjusted according to the required film thickness, it is preferably a film that is structurally a continuous film and is 10 nm or more and 10 μm or less from the viewpoint of sufficiently ensuring the transparency of the film formed by contacting with metal. More preferably, it is 50 nm or more and 5 μm or less. For example, in the case of Nn-octylcarbazole in which the alkyl carbon in the N-alkylcarbazole represented by the above general formula is 8, when a charge amount of 1 mC is applied to 1 cm ^{2 of} the anode, the resulting poly (Nn The film thickness of the (octylcarbazole) film is 16 nm. The film thickness increases in proportion to the energized charge amount.

  Solid poly (N-alkylcarbazole) obtained by electrolytic polymerization forms a transparent conductor by contacting with a metal as described above, but by dissolving the obtained transparent conductor in a solvent, The transparent conductor forming ink described later can be produced.

(Formation of poly (N-alkylcarbazole) by chemical polymerization)
A process of forming poly (N-alkylcarbazole) by chemical polymerization will be described. In the present invention, chemical polymerization means that the polymerizable monomer is oxidatively polymerized by the action of an oxidant without using an energizing means. The poly (N-alkylcarbazole) according to this embodiment can also be formed by chemical polymerization. That is, poly (N-alkylcarbazole) can be obtained by performing chemical polymerization by adding an oxidizing agent to a solvent containing N-alkylcarbazole.

  In chemical polymerization, it is preferable to use a solvent having a relatively high dielectric constant. Examples of the solvent include dichloromethane, chloroform, acetonitrile, dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, methanol, ethanol, γ-butyrolactone, N-methyl-2-pyrrolidone, propylene carbonate, pyridine, dioxane, acetic acid, water and mixtures thereof. Can be used. In the case of chemical polymerization, a larger amount of N-alkylcarbazole can be dissolved in a solvent, and when the weight of the solvent is 100 parts by weight, it may be 0.01 parts by weight or more and 300 parts by weight or less. Preferably, it is 0.1 to 50 parts by weight. By making it 0.01 parts by weight or more, the productivity of the product poly (N-alkylcarbazole) can be increased, and by making it 0.1 parts by weight or more, this effect becomes more remarkable. Moreover, the reaction yield of chemical polymerization can be raised by setting it as 300 parts weight or less, and this effect becomes more remarkable by setting it as 50 parts weight or less.

  Examples of the oxidizing agent include ferric salt, cerium salt, dichromate, permanganate, ammonium persulfate, boron trifluoride, bromate, hydrogen peroxide, chlorine, bromine and iodine. Of these, ferric salts are preferred. An example of the ferric salt is iron (III) perchlorate. By using this iron (III) perchlorate, the degree of polymerization can be increased. The concentration of the oxidizing agent can be appropriately adjusted and is not limited. However, when the weight of the solvent is 100 parts by weight, the concentration is preferably 0.01 parts by weight or more and 500 parts by weight or less. More preferably, it is 1 part by weight or more and 100 parts by weight or less. By setting the content to 0.01 parts by weight or more, the concentration is equal to or higher than that of the starting N-alkylcarbazole, so that the polymerization reaction can be advanced efficiently. It becomes more prominent. Moreover, the viscosity increase of a solution can be suppressed by setting it as 500 parts weight or less, and also a polymerization reaction can be advanced efficiently, and this effect becomes more remarkable by setting it as 100 parts by weight or less.

  In the chemical polymerization, the reaction temperature can be appropriately adjusted depending on the concentration of the oxidizing agent or N-alkylcarbazole, and is not particularly limited, but is preferably −100 ° C. or higher and 100 ° C. or lower, and preferably −80 ° C. or higher and 90 It is more preferable that it is below ℃. There exists an advantage that the electrical conductivity of poly (N-alkyl carbazole) which is a product can be raised by setting it as -80 degreeC or more. Moreover, there exists an advantage that the bridge | crosslinking reaction and peroxidation reaction of poly (N-alkyl carbazole) can be suppressed by setting it as 100 degrees C or less, and the fall of electrical conductivity can be prevented. Further, the reaction time can be appropriately adjusted similarly to the reaction temperature, and is not particularly limited. For example, the reaction time is preferably 1 second or more and 1 week or less, more preferably 1 second or more and 48 hours or less. It is.

  By filtering, washing and drying the solution after the reaction by chemical polymerization, powdery poly (N-alkylcarbazole) can be obtained. These suction filtration, washing, and drying steps may be appropriately performed by known methods. Moreover, a powdery transparent conductor can also be formed by contacting these powders with a metal as described above.

  In the present invention, the polymerization degree of poly (N-alkylcarbazole) obtained by polymerization is preferably 2 to 1000, more preferably 4 to 100, and particularly preferably 4 to 22 from the viewpoint of transparency and strength. .

(Ink for forming transparent conductor)
Another embodiment of the present invention is a transparent conductor forming ink and a method for producing the same. The ink referred to in the present invention is colorless.
As described above, since poly (N-alkylcarbazole) has high solubility in a solvent, it can be made into a solution by mixing with a solvent. Solvents include halogenated hydrocarbons such as dichloroethane, formamides such as dimethylformamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, alcohols such as methanol, lactones such as γ-butyrolactone, N-methyl-2-pyrrolidone and the like. Carbonates such as pyrrolidone and propylene carbonate, ketones such as acetone, and the like can be used. By contacting the obtained poly (N-alkylcarbazole) solution with a metal as described above, the transparent conductor-forming ink of the present invention can be produced. Further, when poly (N-alkylcarbazole) is prepared by chemical polymerization, the transparent conductor forming ink of the present invention can also be prepared by bringing a metal into direct contact with the prepared solution. The contact with the metal can be performed, for example, by immersing a film on which the metal is deposited in the solution, or mixing the metal powder in the solution. Thus, when making it contact with a metal in a solution, it is preferable to use 0.01-300 weight part of metal with respect to 100 weight part of solutions.
The concentration of the transparent conductor forming ink of the present invention can be adjusted as appropriate within the range in which film formation is possible. It is preferable that it is 0.1-1 weight part.

  The transparent conductor forming ink thus prepared can easily produce a transparent conductor having a required size by film forming means such as spin coating, screen printing, and ink jet. It is excellent in that the labor of processing after fabrication can be saved.

Here, based on the said embodiment, the transparent conductor and the ink for transparent conductor formation were actually produced, and the effect of this invention was confirmed. Examples will be described below, but the present invention is not limited to these examples.
The film thickness was measured by cross-sectional observation using a contact-type film thickness measuring machine (Alphastep IQ manufactured by KLA-Tencor) or SEM (Topcon Model ABT-32).

(Synthesis of alkylating agent)
As the alkylating agent used for the production of N-alkylcarbazole, alkyl monobromide was purchased from Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich and Lancaster. Alkylating agents that cannot be purchased as reagents are described in JOHN WILEY & SON, INC. Synthesis was performed by hydrogen iodide addition reaction of alkenes according to the example of published Organic Synthesis IV pages 543-544 (published in 1962).

  A mixture of 3 equivalents of potassium iodide and 4.3 equivalents of 95% by weight orthophosphoric acid was added to 1 equivalent of alkene as a raw material, and the mixture was heated at 80 ° C. for 3 hours with stirring. 95 wt% orthophosphoric acid was prepared by adding 98 wt% phosphoric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) to 85 wt% phosphoric acid. After cooling the reaction solution, water and petroleum ether were added, and the mixture was stirred and separated. The petroleum ether layer was decolorized with 10% by weight sodium thiosulfate, washed with a saturated aqueous sodium chloride solution, and dried over anhydrous sodium sulfate. After evaporation of petroleum ether, alkyl monoiodide was obtained by distillation under reduced pressure.

(Synthesis of N-alkylcarbazole)
Carbazole was dissolved in a 3: 1 (volume ratio) mixed solvent of tetrahydrofuran and N, N-dimethylformamide, and 1 equivalent of the alkyl agent (alkyl bromide or alkyl iodide) obtained above was added to 1 equivalent of carbazole. While stirring, 60% by weight of sodium hydride mineral oil dispersion (trade name “sodium hydride”, manufactured by Kanto Chemical Co., Ltd.) corresponding to 1.5 equivalents of sodium hydride was gradually added and stirred at room temperature for 1 hour. did. To stop the reaction, methanol was added until no bubbles were generated, and then the solvent was removed by evaporation under reduced pressure. Dichloromethane was added to the residue and washed with 3N hydrochloric acid and water. Anhydrous magnesium sulfate was added, dried and filtered. The solvent contained in the obtained filtrate was removed in vacuo, and the residue was purified by silica gel column chromatography using hexane as a developing solvent.

(Synthesis of N-octylcarbazole)
A specific synthesis method will be described by taking a monomer (Nn-octylcarbazole) used for polymerization of poly (Nn-octylcarbazole) as an example.
Carbazole (Tokyo Chemical Industry Co., Ltd., 6.0 g, 0.036 mol) was dissolved in a mixed solution of tetrahydrofuran (30 mL) and N, N-dimethylformamide (10 mL) to give 1-bromooctane (Tokyo Chemical Industry Co., Ltd.). 3.95 g, 0.036 mol), and a 60% by weight sodium hydride mineral oil dispersion (produced by Kanto Chemical Co., Ltd., trade name “sodium hydride”) at room temperature (about 20 ° C.). 16 g, 0.054 mol) was gradually added and stirred for 1 hour to complete the reaction.
After completion of the reaction, methanol was poured into the obtained reaction solution until no bubbles appeared, and the reaction was stopped. After removing the solvent in the reaction solution with an evaporator, the concentrate was extracted with methylene chloride. The organic layer was washed with 3N hydrochloric acid and water, dried over magnesium sulfate, and filtered. Methylene chloride in the filtrate was removed by an evaporator, and the residue was purified by silica gel column chromatography using hexane as a developing solvent. Hexane was removed with an evaporator to obtain a transparent liquid (8 g, yield 80%). It was confirmed by H-NMR that it was Nn-octylcarbazole. The purity was confirmed to be 99.5% by high performance liquid chromatography (HPLC). FIG. 1 shows an NMR chart.

<Example 1>
(Synthesis of poly (Nn-octylcarbazole) by chemical polymerization)
The synthesis of poly (N-alkylcarbazole) by chemical polymerization will be described in detail by taking poly (Nn-octylcarbazole) as an example.
Nn-octylcarbazole (0.14 g, 0.05 mol) as a monomer and iron (III) perchlorate (0.33 g, 0.1 mol) as an oxidizing agent are dissolved in acetonitrile (10 mL), and a nitrogen atmosphere Under stirring at room temperature (about 20 ° C.) for 24 hours, chemical polymerization was performed. The reaction solution was filtered, and the filtrate was washed with methanol and dried at 40 ° C. for 1 hour to obtain the desired poly (Nn-octylcarbazole) green powder (0.21 g). FIG. 2 shows an NMR chart.

(Formation of poly (Nn-octylcarbazole) film)
Poly (Nn-octylcarbazole) 0.1 g obtained by the above chemical polymerization is dissolved in 4 mL of chloroform, and spin-coated at 1,000 rpm using a spin coater (AS-300 manufactured by Able Co., Ltd.) on a slide glass. Coated to form a film. The transmission spectrum of a 100 nm-thick poly (Nn-octylcarbazole) film on the slide glass is shown in FIG. As evident from the spectrum, the film was green. The film thickness was 100 nm. The electrical conductivity of this film by the four-probe method was 7.6 × 10 ⁻⁴ S · cm ⁻¹ .

(Vapor deposition of tin layer)
Next, tin was vapor-deposited with a thickness of 10 nm on the green film of the poly (Nn-octylcarbazole) with a resistance heating vapor deposition apparatus (VPC-260F manufactured by ULVAC Kiko Co., Ltd.). After depositing tin, the resulting film faded away from the metallic luster and green color of tin, and changed to a colorless and transparent film. The transmission spectrum of the resulting colorless and transparent film was measured, and the result is shown in FIG.

(Measurement of electrical conductivity)
The electrical conductivity of the colorless and transparent film having a thickness of 100 nm was measured. The electrical conductivity was measured by a four-probe method using a resistivity meter Loresta GP manufactured by Dia Instruments Co., Ltd. and a four-probe probe MCP-TP06P. As a result, the electric conductivity was 7.5 × 10 ⁻⁴ S · cm ⁻¹ , and it was confirmed that excellent electric conductivity was exhibited.

  As described above, according to this example, it was confirmed that even when a relatively thick film was used, a transparent conductor that maintains good colorless transparency and electrical conductivity and is easy to produce (synthesize) can be obtained.

<Example 2>
(Formation of chemically polymerized poly (Nn-heptylcarbazole) film)
Poly (Nn-heptylcarbazole) 0.1 g obtained by chemical polymerization from n-heptylcarbazole 0.05 mol, iron (III) perchlorate 0.1 mol, and acetonitrile 10 mL was dissolved in 4 mL of chloroform and placed on a slide glass. A spin coater (AS-300 manufactured by Able Co., Ltd., 1,000 rpm) was spin-coated to form a film. The transmission spectrum of the poly (Nn-heptylcarbazole) film on the slide glass is shown in FIG. As is apparent from the transmission spectrum and the photograph of FIG. 5, the poly (Nn-heptylcarbazole) film was green. The electrical conductivity of this film by the four-probe method was 4.0 × 10 ⁻⁵ S · cm ⁻¹ .

(Vapor deposition of tin layer)
Next, tin was vapor-deposited on the green poly (Nn-heptylcarbazole) film with a thickness of 10 nm using a resistance heating vapor deposition apparatus (VPC-260F manufactured by ULVAC Kiko Co., Ltd.). As shown in the photograph of FIG. 5, the obtained film was vapor-deposited with tin, and then the metallic luster and green color of tin faded to change to a colorless and transparent film. The transmission spectrum of the resulting colorless and transparent film was measured, and the result is shown in FIG.

(Measurement of electrical conductivity)
The electrical conductivity of the colorless and transparent film having a thickness of 100 nm was measured. This measurement was performed in the same manner as in Example 1. As a result, the electric conductivity was 1.4 × 10 ⁻⁴ S · cm ⁻¹ , and it was confirmed that excellent electric conductivity was exhibited.

<Example 3>
(Production of chemically polymerized poly (Nn-nonylcarbazole) film)
Poly (Nn-nonylcarbazole) 0.1 g obtained by chemical polymerization from 0.05 mol of n-nonylcarbazole, 0.1 mol of iron (III) perchlorate, and 10 mL of acetonitrile was dissolved in 4 mL of chloroform and placed on a slide glass. Using a spin coater (AS-300 manufactured by Able Co., Ltd.), a film was formed by spin coating at 1,000 rpm. The transmission spectrum of a 200 nm-thick poly (Nn-nonylcarbazole) film on a slide glass is shown in FIG. As is clear from the transmission spectrum, the poly (Nn-nonylcarbazole) film was green. The electrical conductivity of this film by the four-probe method was 4.0 × 10 ⁻⁵ S · cm ⁻¹ .

(Vapor deposition of tin layer)
Next, tin was deposited to a thickness of 10 nm on the green film of poly (Nn-nonylcarbazole) by a resistance heating vacuum deposition method. Similar to the above poly (Nn-octylcarbazole) film and poly (Nn-heptylcarbazole) film, after depositing tin, the metallic luster and green color of tin both fade. It changed to a colorless and transparent film. The transmission spectrum of the resulting colorless and transparent film was measured, and the result is shown in FIG.

(Measurement of electrical conductivity)
The electric conductivity of the colorless and transparent film having a thickness of 200 nm was measured. This measurement was performed by a four-probe method using a resistivity meter Loresta GP manufactured by Dia Instruments Co., Ltd. and a four-probe probe MCP-TP06P. As a result, the electric conductivity was 1.4 × 10 ⁻⁴ S · cm ⁻¹ , and it was confirmed that excellent electric conductivity was exhibited.

<Example 4>
(Ink for forming transparent conductor)
In Example 1, 0.1 g of poly (N-octylcarbazole) obtained by chemical polymerization was dissolved in 4 mL of 1,2-dichloroethane, and tin was then added thereto using a resistance heating vapor deposition apparatus (VPC-260F manufactured by ULVAC Kiko Co., Ltd.). 90 cm ² of a commercially available polyester film (Lumirror film manufactured by Toray Industries, Inc.) deposited with a thickness of 200 nm was prepared to prepare a transparent conductor forming ink. When the polyester film was taken out, the tin on the polyester film disappeared, and the green solution turned grayish black.

(Formation of transparent conductor film)
This ink was spin-coated on a slide glass at a rotation speed of 1,000 rpm using a spin coater (AS-300 manufactured by Able Co., Ltd.) to form a transparent conductor film. The film thickness of the produced transparent conductor film was 100 nm. The transmission spectrum of this membrane is shown in FIG. The electric conductivity of this film by the four-probe method was 9.5 × 10 ⁻² S · cm ⁻¹ . It was confirmed that this film exhibited very excellent electrical conductivity.

<Example 5>
(Ink for forming transparent conductor)
A commercially available polyester film in which 0.1 g of poly (N-octylcarbazole) obtained by chemical polymerization in Example 1 was dissolved in 4 mL of 1,2-dichloroethane and aluminum was deposited thereon by 70 nm (Mylar PET film manufactured by DuPont). ) 75 cm ² was added to prepare a transparent conductor forming ink. When the polyester film was taken out, the tin on the polyester film disappeared, and the green solution turned grayish black.

(Formation of transparent conductor film)
This ink was spin-coated on a slide glass at a rotation speed of 1,000 rpm using a spin coater (AS-300 manufactured by Able Co., Ltd.) to form a transparent conductor film. The film thickness of the produced transparent conductor film was 100 nm. The transmission spectrum of this film is shown in FIG. The electric conductivity of this film by the four-probe method was 4.5 × 10 ⁻⁴ S · cm ⁻¹ . It was confirmed that this film showed very excellent electrical conductivity.

<Example 6>
(Ink for forming transparent conductor)
Using N-ethylhexylcarbazole (manufactured by Aldrich), 0.1 g of poly (N-ethylhexylcarbazole) obtained by chemical polymerization in the same manner as the poly (N-octylcarbazole) of Example 1 was subjected to 1,2-dichloroethane. Dissolved in 4 mL, 0.15 g of granular tin was added thereto, and a transparent conductor forming ink was prepared. Part of the added tin was dissolved. The remaining tin particles were removed by filtration. The solution that was green turned grayish black.

(Formation of transparent conductor film)
This ink was spin-coated on a slide glass at a rotation speed of 2,000 rpm using a spin coater (Mikasa Co., Ltd. MS-A150) to form a transparent conductor film. The film thickness of the produced transparent conductor film was 100 nm. The electrical conductivity of this film by the four-probe method was 2.0 × 10 ⁰ S · cm ⁻¹ . It was confirmed that this film showed very excellent electrical conductivity.

<Example 7>
(Ink for forming transparent conductor)
0.1 g of poly (Nn-octylcarbazole) obtained by chemical polymerization in Example 1 was dissolved in 4 mL of chloroform, and 0.1 g of granular magnesium was added thereto to prepare a transparent conductor forming ink. The added magnesium partially dissolved. The remaining magnesium particles were removed by filtration. The solution that was green turned grayish black.

(Formation of transparent conductor film)
This ink was spin-coated on a slide glass at a rotation speed of 2,000 rpm using a spin coater (Mikasa Co., Ltd. MS-A150) to form a transparent conductor film. The film thickness of the produced transparent conductor film was 100 nm. The transmission spectrum of this membrane is shown in FIG. The electric conductivity of this film by the four-probe method was 4.0 × 10 ⁻³ S · cm ⁻¹ . It was confirmed that this film showed very excellent electrical conductivity.

<Example 8>
(Ink for forming transparent conductor)
0.1 g of poly (Nn-octylcarbazole) obtained by chemical polymerization in Example 1 was dissolved in 4 mL of chloroform, and 0.25 g of granular zinc was added thereto to prepare a transparent conductor forming ink. Part of the added granular zinc was dissolved. The remaining zinc particles were removed by filtration. The solution that was green turned grayish black.

(Formation of transparent conductor film)
This ink was spin-coated on a slide glass at a rotation speed of 2,000 rpm using a spin coater (Mikasa Co., Ltd. MS-A150) to form a transparent conductor film. The film thickness of the produced transparent conductor film was 100 nm. The transmission spectrum of this membrane is shown in FIG. The electric conductivity of this film by the four-probe method was 4.0 × 10 ⁻³ S · cm ⁻¹ . It was confirmed that this film showed very excellent electrical conductivity.

<Example 9>
(Ink for forming transparent conductor)
0.1 g of poly (Nn-octylcarbazole) obtained by chemical polymerization in Example 1 was dissolved in 4 mL of chloroform, and 0.35 g of granular indium was added thereto to prepare a transparent conductor forming ink. Part of the added granular indium was dissolved. The remaining indium particles were removed by filtration. The solution that was green turned grayish black.

(Formation of transparent conductor film)
This ink was spin-coated on a slide glass at a rotation speed of 2,000 rpm using a spin coater (Mikasa Co., Ltd. MS-A150) to form a transparent conductor film. The film thickness of the produced transparent conductor film was 100 nm. The transmission spectrum of this membrane is shown in FIG. The electrical conductivity of this film by the four-probe method was 7.1 × 10 ⁻³ S · cm ⁻¹ . It was confirmed that this film showed very excellent electrical conductivity.

<Example 10>
(Ink for forming transparent conductor)
0.1 g of poly (Nn-octylcarbazole) obtained by chemical polymerization in Example 1 was dissolved in 4 mL of chloroform, heated at 40 ° C. and 0.2 g of molten gallium was added with a dropper to form a transparent conductor. An ink was prepared. The added gallium was partially dissolved in the solution and then solidified into particles. The remaining gallium particles were removed by filtration. The solution that was green turned grayish black.

(Formation of transparent conductor film)
This ink was spin-coated on a slide glass at a rotation speed of 2,000 rpm using a spin coater (Mikasa Co., Ltd. MS-A150) to form a transparent conductor film. The film thickness of the produced transparent conductor film was 100 nm. The transmission spectrum of this membrane is shown in FIG. The electrical conductivity of this film by the four-probe method was 4.9 × 10 ⁻³ S · cm ⁻¹ . It was confirmed that this film showed very excellent electrical conductivity.

<Example 11>
(Formation of transparent conductor film by pressure bonding with molten metal)
Poly (Nn-octylcarbazole) 0.1 g obtained by chemical polymerization in Example 1 was dissolved in 4 mL of chloroform, and spin-coated on a slide glass with a spin coater (MS-A150 manufactured by Mikasa Co., Ltd.) to form a film. did. Molten gallium heated to 40 ° C. is poured onto a tray, covered with a slide glass film made of poly (Nn-octylcarbazole), and poly (Nn-octylcarbazole) spin coating using the weight of the slide glass The film and molten gallium were pressure-bonded and heated to 40 ° C. The spin coat film that was green became colorless and transparent. The transmission spectrum of this membrane is shown in FIG. The electrical conductivity of this film by the four-probe method was 2.0 × 10 ⁻³ S · cm ⁻¹ . It was confirmed that this film showed very excellent electrical conductivity.

<Example 12>
(Formation of transparent conductor film by pressure bonding with molten metal)
Poly (Nn-octylcarbazole) 0.1 g obtained by chemical polymerization in Example 1 was dissolved in 4 mL of chloroform, and spin-coated on a slide glass with a spin coater (MS-A150 manufactured by Mikasa Co., Ltd.) to form a film. did. An alloy of 75.5% by weight of gallium melted at room temperature and 24.5% by weight of indium is poured onto a tray, covered with a slide glass on which poly (Nn-octylcarbazole) is formed, and the weight of the slide glass is reduced. A poly (Nn-octylcarbazole) spin coat film and molten gallium were pressure-bonded using them. The spin coat film that was green became colorless and transparent. The transmission spectrum of this film is shown in FIG. The electrical conductivity of this film by the four-probe method was 1.0 × 10 ⁻³ S · cm ⁻¹ . It was confirmed that this film showed very excellent electrical conductivity.

<Example 13>
(Formation of transparent conductive film made of chemically polymerized poly (Nn-ethylcarbazole))
Chemical polymerization was carried out from 0.05 mol of n-ethylcarbazole, 0.1 mol of iron (III) perchlorate, and 10 mL of acetonitrile under the same polymerization conditions as for the preparation of Nn-octylcarbazole. 0.1 g of the obtained poly (Nn-ethylcarbazole) was dissolved in 4 mL of chloroform and reacted by adding 0.15 g of granular aluminum, and then the remaining aluminum particles were removed by filtration to form a transparent conductor. An ink was prepared. Further, in order to remove fine insoluble matter, the solution was filtered with a plastic disc syringe filter (model number 3784-1302, pore size 0.2 μm) manufactured by Whatman Japan, and then a spin coat film was formed on a slide glass at 2,000 rpm. As the spin coater, MS-A150 manufactured by Mikasa Co., Ltd. was used. The transmission spectrum of this film is shown in FIG. The electrical conductivity of this film by the four-probe method was 2.0 × 10 ⁻⁴ S · cm ⁻¹ .

<Example 14>
(Formation of transparent conductive film made of chemically polymerized poly (Nn-docosylcarbazole))
Chemical polymerization was performed from 0.05 mol of n-docosylcarbazole, 0.1 mol of iron (III) perchlorate, and 10 mL of acetonitrile under the same polymerization conditions as those for the preparation of Nn-octylcarbazole. 0.1 g of the obtained poly (Nn-docosylcarbazole) was dissolved in 4 mL of chloroform, 0.15 g of granular tin was added and reacted, and then the remaining tin particles were removed by filtration to obtain a transparent conductor. A forming ink was prepared. The solution that was green turned grayish black. This ink was spin-coated on a slide glass at a rotational speed of 2,000 rpm with a spin coater (Mikasa Co., Ltd. MS-A150) to form a transparent conductor film. The film thickness of the produced transparent conductor film was 100 nm. The transmission spectra of this film and the poly (Nn-docosylcarbazole) film are shown in FIG. The electrical conductivity of this film by the four-probe method was 3.8 × 10 ⁻⁴ S · cm ⁻¹ .

<Reference Example 15>
(Measurement of ionization potential of poly (Nn-octylcarbazole) film)
0.1 g of poly (Nn-octylcarbazole) obtained by chemical polymerization in Example 1 was dissolved in 4 mL of chloroform, and spin-coated with a spin coater (MS-A150, manufactured by Mikasa Co., Ltd.) on a silicon wafer. did. The ionization potential of this film by ultraviolet photoelectron spectroscopy with ESCA-5400 manufactured by ULVAC-PHI Co., Ltd. was 5.2 eV. The photoelectron spectrum is shown in FIG.

<Reference Example 16>
(Measurement of ionization potential of poly (Nn-docosylcarbazole) film)
0.1 g of poly (Nn-docosylcarbazole) obtained by chemical polymerization in Example 14 was dissolved in 4 mL of chloroform, and spin coated with a spin coater (MS-A150, manufactured by Mikasa Co., Ltd.) on a silicon wafer. Filmed. The ionization potential of this film by ultraviolet photoelectron spectroscopy with ESCA-5400 manufactured by ULVAC-PHI Co., Ltd. was 5.0 eV. The photoelectron spectrum is shown in FIG.

<Comparative Example 1>
An electrolytic solution composed of a dichloromethane solution in which carbazole (5 mM) and tetrabutylammonium perchlorate (0.1 M), which are commercially available, were dissolved was placed in the main chamber of a two-room type electrolytic cell made of heat-resistant glass. Then, a glass electrode coated with an ITO film (film thickness: 170 nm) and a platinum plate electrode were immersed in this main chamber. On the other hand, in the subchamber separated by the sintered glass film, an electrolytic solution composed of a dichloromethane solution in which tetrabutylammonium perchlorate (0.1 M) was dissolved was placed, and SCE was immersed therein. Nitrogen gas was passed through the solution in the main chamber for 40 minutes to eliminate dissolved oxygen. The ITO glass electrode was connected to a constant potential power source (potentiostat) using the working electrode, the platinum plate electrode as the counter electrode, and the SCE as the reference electrode. A potential of +1.2 V was applied to the working electrode relative to the reference electrode. The amount of electricity applied was 50 mC / cm ² , and during electrolysis, nitrogen gas was allowed to flow above the electrolyte to maintain a nitrogen atmosphere. The electrolysis cell was installed in a thermostat and the electrolysis temperature was kept at 5 ° C.

  By this operation, a polycarbazole film having a thickness of 800 nm was formed on the ITO glass electrode. This film was not dissolved in dichloromethane, chloroform, and 1,2-dichloroethane, and ink could not be prepared.

  By the production method of the present invention, a transparent conductor and a transparent conductor-forming ink can be easily obtained, and can be applied to display devices such as liquid crystal displays and electroluminescent displays. Moreover, it is applicable also to a solar cell, a touch panel, etc., and is industrially useful.

Claims (5)

A liquid phase comprising poly (N-alkylcarbazole) obtained by chemical polymerization of at least one N-alkylcarbazole represented by the following general formula and a metal having a work function smaller than that of the poly (N-alkylcarbazole). The manufacturing method of the transparent conductor including the process made to contact in.
(In the formula, n is an integer of 1 or more, and at least one hydrogen of alkyl may be replaced with at least one group selected from hydroxy, carboxyl, sulfo and amino.) A transparent conductor produced by the method according to claim 1 . A poly (N-alkylcarbazole) obtained by chemical polymerization of at least one N-alkylcarbazole represented by the following general formula is dissolved in a solvent to form a poly (N-alkylcarbazole) solution. A method for producing an ink for forming a transparent conductor, comprising a step of bringing a metal having a work function smaller than that of (N-alkylcarbazole) into contact in a liquid phase.
(In the formula, n is an integer of 1 or more, and at least one hydrogen of alkyl may be replaced with at least one group selected from hydroxy, carboxyl, sulfo and amino.) A solution of a poly (N-alkylcarbazole) solution obtained by chemical polymerization of at least one N-alkylcarbazole represented by the following general formula and a metal having a work function smaller than that of the poly (N-alkylcarbazole) A method for producing an ink for forming a transparent conductor, comprising a step of contacting in a phase.
(In the formula, n is an integer of 1 or more, and at least one hydrogen of alkyl may be replaced with at least one group selected from hydroxy, carboxyl, sulfo and amino.) An ink for forming a transparent conductor produced by the method according to claim 3 or 4 .